Table 2.
Concentrations of metabolites identified in various rumen fluids
| Metabolite | Avg concn (μM) ± SDa |
|||
|---|---|---|---|---|
| HGS | HFS | HDC | KNG | |
| Organic acids | ||||
| Acetate (mM) | 78.9 ± 1.9 | 69.7 ± 1.1 | 63.2 ± 2.16 | 43.7 ± 2.7 |
| Propionate (mM) | 15.2 ± 1.0 | 15.9 ± 1.3 | 15.8 ± 0.9 | 14.7 ± 0.3 |
| Butyrate (mM) | 8.04 ± 0.6 | 9.78 ± 0.5 | 10.8 ± 1.1 | 11.6 ± 1.5 |
| Valerate (mM) | 2.12 ± 0.1 | 2.07 ± 0.1 | 1.84 ± 0.2 | 4.59 ± 0.4 |
| Isobutyrate (mM) | 1.32 ± 0.2 | 1.33 ± 0.1 | 3.61 ± 0.4 | 2.26 ± 0.3 |
| Lactate | 382 ± 39 | 331 ± 36 | 238 ± 14 | 1,400 ± 160 |
| 3-Phenylpropionate | 453 ± 21 | 397 ± 23 | 862 ± 36 | 766 ± 32 |
| Acetoacetate | 141 ± 16 | 84.7 ± 17 | 70.8 ± 6.9 | 564 ± 56 |
| Formate | 154 ± 16 | 105 ± 28 | 75.6 ± 15 | 556 ± 99 |
| Fumarate | 23.8 ± 4.2 | 28.5 ± 8.7 | 25.1 ± 4.0 | 266 ± 49 |
| 3-Hydroxybutyrate | 131 ± 8.0 | 80.1 ± 9.4 | 76.5 ± 17 | 606.3 ± 14 |
| Isovalerate | 726 ± 99 | 681 ± 120 | 533 ± 82 | 1,280 ± 98 |
| Phenylacetate | 379 ± 26 | 343 ± 22 | 219 ± 6.4 | 708 ± 77 |
| 3-Hydroxyphenylacetate | 104 ± 4.3 | 54.5 ± 2.0 | 62.0 ± 3.0 | 293 ± 31 |
| Succinate | 77.3 ± 13 | 73.0 ± 11 | 49.1 ± 8.2 | 240 ± 49 |
| Total organic acids (mM) | 108.1 | 100.1 | 88.4 | 83.6 |
| Amino acids | ||||
| Alanine | 231 ± 51 | 184 ± 54 | 109 ± 26 | 748 ± 51 |
| Aspartate | 410 ± 51 | 252 ± 9.7 | 159 ± 6.2 | 858 ± 67 |
| Glutamate | 479 ± 45 | 341 ± 46 | 256 ± 18 | 811 ± 76 |
| Glycine | 143 ± 34 | 200 ± 45 | 60.3 ± 9.9 | 617 ± 79 |
| Histidine | 171 ± 24 | 164 ± 63 | 71.4 ± 13 | 423 ± 61 |
| Isoleucine | 216 ± 25 | 231 ± 48 | 128 ± 4.1 | 1,060 ± 150 |
| Leucine | 122 ± 46 | 132 ± 20 | 95.3 ± 13 | 487 ± 84 |
| Lysine | 188 ± 30 | 189 ± 17 | 115 ± 24 | 1,030 ± 65 |
| Phenylacetylglycine | 224 ± 12 | 303 ± 68 | 98.1 ± 20 | 511 ± 22 |
| Proline | 418 ± 86 | 399 ± 90 | 289 ± 49 | 1,230 ± 45 |
| Tyrosine | 159 ± 30 | 162 ± 33 | 82.0 ± 14 | 438 ± 33 |
| Valine | 187 ± 12 | 197 ± 31 | 94.1 ± 23 | 549 ± 44 |
| Amines | ||||
| Methylamine | 445 ± 44 | 489 ± 63 | 213 ± 32 | 2,240 ± 150 |
| Cadaverine | 107 ± 1.8 | 104 ± 4.8 | 61.3 ± 7.2 | 514 ± 33 |
| Dimethylamine | 148 ± 9.4 | 164 ± 17 | 75.5 ± 2.0 | 213 ± 29 |
| Miscellaneous | ||||
| Choline | 23.0 ± 2.9 | 16.9 ± 8.2 | 12.1 ± 1.8 | 115 ± 9.2 |
a
Data are presented as average values measured in triplicate (metabolite concentrations are presented as μM concentrations [unless stated otherwise in column 1] ± mean standard deviations). Ruminant abbreviations are as defined in Table 1, footnote a.